I think the situation would be at a restaurant or cafeteria. We have several ways of saying it for the formality.
If you are with your friends:
(Formal) 外の席と中の席(or 外と中)、どちらが良いですか。
(Informal) 外と中、どっちがいい? / 外にする?中にする?
If you are waitress, you should say (to customers): 外のお席と中のお席、どちらになさいますか / どちらがよろしいでしょうか。
If I understood wrong, please let me know with the situation and whom you are talking with.
I hope this was helpful.